This invention relates to hydraulic systems, and more specifically to directional control valving in high pressure hydraulic systems.
Many differing types of apparatus employ hydraulic systems utilizing directional valves. In most instances, the directional valves are of the spool type with the consequence that when utilized in a system having a relatively large capacity, system pressure must be limited to no more than about 4500 psi due to leakage and structural problems. The flow output of such valves is often affected by the loading on the system in which they are employed and frequently relatively high power hydraulic pilot systems are required to minimize operator effort in effecting system operation through valves or the like.